A descriptive term that attempts to group many individual singers into basic categories. Singers of the same voice type will tend to possess similar ranges, colors, and tessituras….Voice types should not be confused with the four basic choral parts: soprano, alto, tenor and bass. While many singers may find that they are most comfortable on the choral part that has the same name as their voice type, their part assignment is often a general label and not reflective of their true, specific identity.
(Hoch, ‘A Dictionary for the Modern Singer,’ 2014, p. 194)
In classical singing (specifically operatic singing), one’s specific voice type. By extension, one’s Fach also dictates which operatic roles one would sing. Narrowly, the Fach system refers to the Kloiber Fach System or German Fach System, which is traditionally used in the opera houses of Germany and Austria…The Fach system is generally not used in other parts of the world, and professional singers from all nationalities generally sing roles from multiple Fächer once their careers are established.
(Hoch, ‘A Dictionary for the Modern Singer,’ 2014, p. 63)